The Chicago Zoological Society is uniquely positioned to expand our leadership role in conservation on a local, regional, national, and international level. Our approach to applied science and education has led to a history of significant programs that have directly benefited the conservation of wildlife and the natural world.

To maximize and sustain conservation impact, programs must integrate and apply scientific knowledge toward human action while leveraging cultural shifts through training, community engagement, strategic collaborations, and public policy involvement. The management team—along with the Board of Trustees of the Chicago Zoological Society—is accountable for leading CZS toward desired strategic outcomes that advance the institution.

Based on rigorous review and evaluation of the best available data and alternatives, our leadership team functions collaboratively in a trusting and respectful environment, passionately committed to the mission of inspiring conservation leadership by engaging people and communities with wildlife and nature.

Dr. Michael Adkesson, President & CEO of the Chicago Zoological Society, Director of Brookfield Zoo

Dr. Mike Adkesson is a renowned leader in the care of zoo animals and conservation of wildlife.  He is a passionate advocate for the importance of modern zoos and aquariums as a means of inspiring societal compassion and concern for wildlife and nature.  With board-certification from the American College of Zoological Medicine and the European College of Zoological Medicine, Dr. Adkesson is one of only a small group of specialists in the veterinary care of zoo animals and wildlife.  

Prior to being appointed President & CEO, Dr. Adkesson worked as a clinical veterinarian and later Vice President of Clinical Medicine at Brookfield Zoo.  During his tenure, the veterinary department set new standards for the medical care of zoo animals, pushing the boundaries and standards of care for zoo patients.  The department launched new initiatives in zoo-focused veterinary radiology, advanced imaging, anesthesia, and conservation medicine.  Over the past decade, the zoo’s veterinary education program also became one of the most sought after and premier programs globally.

Since 2007, Mike also led the zoo’s conservation programs in coastal Peru focusing on endangered Humboldt penguins, Peruvian fur seals, South American sea lions, and other marine species in coastal Peru.  This passion has resulted in field research, capacity building, and community education programs that are making a positive conservation impact in Peru.  As an associate researcher for Cayetano Heredia University in Lima, Peru, he has also mentored numerous students who have gone on to their own careers in conservation.

Dr. Adkesson is a past-president of the American Association of Zoo Veterinarians and a professional fellow of the Association of Zoos and Aquariums, as well as being actively involved in many other professional organizations.  He is an adjunct faculty member with the University of Illinois College of Veterinary Medicine and has trained numerous veterinary and graduate students.  As an accomplished researcher and clinician, Dr. Adkesson is also the author of over a hundred peer-reviewed publications and conference proceedings.

Dr. Adkesson received his doctor of veterinary medicine degree with honors from the University of Illinois.  Following a clinical internship year in companion animal medicine and surgery, Dr. Adkesson completed three years of residency training in zoological medicine at the University of Missouri and Saint Louis Zoo.  In addition to being a board-certified veterinarian, Mike holds a Master’s degree in Business Administration from the University of Illinois Gies College of Business.  

David Burns, Chief Financial & Administrative Officer
Dave Burns

David Burns has over 25 years of finance and accounting experience in both the private and public sectors, most recently serving as the Chief Financial Officer (CFO) for the Chicago Housing Authority. There, he was responsible for a team of 45 employees and a $1 billion operating budget.

David is a Certified Public Accountant and possesses a Bachelor’s degree in Accounting from Monmouth College. He has deep experience in finance and accounting, including budgeting, debt management, financial analysis and forecasting, implementation of systems and controls, working with auditors, legal counsel, external organizations, collective bargaining, strategic planning, capital construction, and much more.

William Zeigler, Senior Vice President of Animal Programs
Bill Zeigler

Bill Zeigler is a nationally recognized expert in project innovation and animal management of zoological parks, wildlife/education centers and species survival programs, committed to wildlife conservation and animal care and welfare. He is recognized in the zoo and aquarium world for his innovative ideas and management skills that enhance institutional operations and animal-related programs.

His career began as a keeper at the Crandon Park Zoo, where he quickly assumed a leadership role in the zoo’s design, construction, relocation and transformation into a new, 760-acre Miami Metrozoo in Dade County, Florida (now called Zoo Miami). He served as the zoo’s General Curator, and held a number of leadership positions in the Association of Zoos and Aquariums (AZA) including on the Wildlife Conservation Management Committee (WCMC). He founded several Taxonomic Advisory Groups (TAGs) and Species Survival Plans (SSPs) and is an experienced leader in developing in-situ and ex-situ wildlife conservation and research programs.

In 1996, he joined Ogden Entertainment and managed every aspect of multiple facilities – including Design Development, animal collection and management programming, and business operations. Thereafter, he worked 12 years as an independent consultant for institutions and organizations globally seeking to improve their operations and programs, including fundraising, board development, master planning, exhibit design, public relations and collection planning.

In 2010, he joined the Chicago Zoological Society, where he oversees all aspects of animal care and management as the Senior Vice President of Animal Programs. He continues to develop and enhance Brookfield Zoo’s Center for the Science of Animal Welfare (CSAW), elevating the organization’s animal programs to a leadership role in the zoological profession.

Sarah Breen Bartecki, Senior Vice President,Conservation Programs, Research, and Funding

Sarah Breen Bartecki has more than 25 years’ experience in nonprofit management, strategic planning, fundraising, program development, and financial analysis.

Sarah received a Bachelor in Arts degree from Northwestern University and a Masters in Business Administration from the University of Chicago Booth Graduate School of Business, with concentrations in general management and managerial and organizational behavior.

Prior to joining the Chicago Zoological Society, Sarah worked at the Chicago Botanic Garden. She is a dedicated conservationist with a passion for inspiring young people, engaging diverse voices in conservation, and restoring biodiversity and people’s connection to wildlife and nature.

Jennifer Baader, Senior Vice President of Government Affairs

Jennifer Baader is an experienced and effective advocate for environmental issues at the local, state and federal levels.

Jennifer received her Bachelor of Science degree at the University of Illinois and earned her Juris Doctorate at Chicago-Kent College of Law with a Certificate in Environmental and Energy Law. She has held prior positions with the U.S. Environmental Protection Agency (EPA) Region 5 office, the Chicago Park District, Openlands and the Illinois Pollution Control Board. A passion for environmental law led Jennifer to the Illinois House of Representatives as Assistant Counsel. In that position, she addressed emerging public policy issues as the lead counsel to the environment, energy, public utilities, mass transit and local government committees. Most recently, Jennifer also guided a global corporation’s international partnerships, as well as their advocacy efforts before Congress in Washington D.C. and locally.

Sandi Dornhecker, Senior Vice President of Human Resources

Sandi Dornhecker is an experienced Human Resources leader with over 25 years’ of HR experience in both the for-profit and non-profit sectors. She has a passion for animals and conservation, which led her to her dream job at Brookfield Zoo.

She holds a Bachelor’s degree in Behavioral Science from National Louis University and has completed graduate work towards an M.B.A. degree in Human Resources. Sandi directs the human resources function for the Chicago Zoological Society for a workforce of roughly 345 full-time and several hundred seasonal and part-time employees. She is responsible for strategic HR planning; recruitment, placement, and orientation; compensation and benefits; employee and labor relations; policy development and interpretation; Human Resource Information Systems; staff training and development; legal compliance; organizational development and change management.

Prior to her work at Brookfield Zoo, she worked as the Director of Human Resources for the Illinois Cancer Center, a non-profit cancer research consortium of university medical centers, teaching schools, and hospitals in Illinois. She has also held various other management and administrative positions in the corporate sector earlier in her career.

She is a member of the Society for Human Resource Management (SHRM), the Society for Young American Professionals, and she has been listed in Marquis’ Who’s Who since 1998. She received the Kelly Award of Excellence, among other awards. In 2000, she co-founded the Chicago Metropolitan HR Cultural Group, a professional group of top HR officers and professionals representing major Chicagoland cultural and non-profit organizations. She has consulted for a variety of organizations and served as a presenter and trainer for colleges and community and professional groups.

Dr. Sathya Chinnadurai, Senior Vice President of Animal Health

Dr. Sathya Chinnadurai leads the Animal Health and Welfare group, which includes veterinary services and clinical operations, the conservation medicine program, the welfare and conservation science program, and nutrition services. This multi-departmental group oversees the healthcare and nutrition of all the animals at Brookfield Zoo and is a nationally-recognized leader in welfare, conservation, and veterinary research.

Dr. Chinnadurai obtained his Doctor of Veterinary Medicine degree from the University of Missouri, where he also completed a Master’s degree in wildlife sciences. He is a board-certified specialist in both zoological medicine and veterinary anesthesiology, following the completion of successive residency training programs in both fields at the North Carolina State University College of Veterinary Medicine. In 2018, Dr. Chinnadurai completed the requirements to also become a board-certified diplomate of the American College of Animal Welfare. He is an associate editor for the anesthesia section of the Journal of Zoo and Wildlife Medicine and is a prolific scientific author. For the past several years Dr. Chinnadurai has also served as a member of the Morris Animal Foundation Wildlife Scientific Advisory Board and the Animal Welfare Committee of the American Veterinary Medical Association, as well as representing the American Association of Zoo Veterinarians on the AVMA House Advisory Panel. He is a prolific researcher, writer, educator, and mentor.


Center for the Science of Animal Welfare

Read about our innovative practices in animal welfare to ensure the ultimate care of our individual animals.

Classes and Camps

Center for Conservation Leadership

We place a high priority on developing and supporting conservation leaders of all ages and backgrounds.


Visit Brookfield Zoo

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